I just got this Error Message once last night after upgrading to a new version of 360. I ran a Quick Virus Scan and when it appeared to finish scanning the Error: "8504,104" came up. I clicked the Fix Error button and it could not find a fix. I went into Norton's web site and found the following instructions to fix this error: https://support.norton.com/sp/en/us/home/current/solutions/v62545568_EndUserProfile_en_us
I downloaded Norton Power Eraser and the Norton Removal Tool but have not run them yet nor have performed these instructions yet. After reading a number of posts in this forum, I am not sure if this will work. It seems there is problem with Norton lately, because my other PC got infected by some malware/virus at the Root Level and now I am in the process of re-installing everything.
I am reluctant on running these instructions just yet, because I said I only got the error message once last night while running the Quick Virus Scan while Windows Update was running in background. I rebooted my PC and re-ran the the Quick Virus Scan again without an error message. So I am not sure if it is worth my risk to uninstall 360 and reinstall it. I think the issue came up because Windows Update was running at the same time and their Malicious Software Tool could have cased the error message.
Anyway does anyone one that if the Error Message does not show up again during a Virus Scan, is my 360 working properly or not? A chat session with Norton Technical support advises me to remove Norton and re-install it just to be sure that it is properly installed.